Best electronic tester this product on the diagnosis of automotive electronic system, which lets you reduce the time of diagnosis, then will instrument and auto battery are connected by operating switches, positive or negative battery voltage to the distal end of the probe, the instrument with short circuit protection function, can be used for instant bad grounding short circuit test, tracking and positioning, or used to measure DC voltage value, and the auxiliary grounding wire with the use, and can be used for on-off test instrument, long cable allows you to easily test.